target/linux/generic/backport-5.10/841-v5.15-leds-pca955x-add-brightness-get-function.patch

   1 From 7086625fde6538b2c0623eb767ad23c7ac3d7f3a Mon Sep 17 00:00:00 2001
   2 From: Eddie James <eajames@linux.ibm.com>
   3 Date: Fri, 16 Jul 2021 17:03:28 -0500
   4 Subject: [PATCH] leds: pca955x: Add brightness_get function
   5
   6 Add a function to fetch the state of the hardware LED.
   7
   8 Signed-off-by: Eddie James <eajames@linux.ibm.com>
   9 Signed-off-by: Pavel Machek <pavel@ucw.cz>
  10 ---
  11  drivers/leds/leds-pca955x.c | 52 +++++++++++++++++++++++++++++++++++++
  12  1 file changed, 52 insertions(+)
  13
  14 --- a/drivers/leds/leds-pca955x.c
  15 +++ b/drivers/leds/leds-pca955x.c
  16 @@ -233,6 +233,57 @@ static int pca955x_read_ls(struct i2c_cl
  17         return 0;
  18  }
  19
  20 +static int pca955x_read_pwm(struct i2c_client *client, int n, u8 *val)
  21 +{
  22 +       struct pca955x *pca955x = i2c_get_clientdata(client);
  23 +       u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
  24 +       int ret;
  25 +
  26 +       ret = i2c_smbus_read_byte_data(client, cmd);
  27 +       if (ret < 0) {
  28 +               dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
  29 +                       __func__, n, ret);
  30 +               return ret;
  31 +       }
  32 +       *val = (u8)ret;
  33 +       return 0;
  34 +}
  35 +
  36 +static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
  37 +{
  38 +       struct pca955x_led *pca955x_led = container_of(led_cdev,
  39 +                                                      struct pca955x_led,
  40 +                                                      led_cdev);
  41 +       struct pca955x *pca955x = pca955x_led->pca955x;
  42 +       u8 ls, pwm;
  43 +       int ret;
  44 +
  45 +       ret = pca955x_read_ls(pca955x->client, pca955x_led->led_num / 4, &ls);
  46 +       if (ret)
  47 +               return ret;
  48 +
  49 +       ls = (ls >> ((pca955x_led->led_num % 4) << 1)) & 0x3;
  50 +       switch (ls) {
  51 +       case PCA955X_LS_LED_ON:
  52 +               ret = LED_FULL;
  53 +               break;
  54 +       case PCA955X_LS_LED_OFF:
  55 +               ret = LED_OFF;
  56 +               break;
  57 +       case PCA955X_LS_BLINK0:
  58 +               ret = LED_HALF;
  59 +               break;
  60 +       case PCA955X_LS_BLINK1:
  61 +               ret = pca955x_read_pwm(pca955x->client, 1, &pwm);
  62 +               if (ret)
  63 +                       return ret;
  64 +               ret = 255 - pwm;
  65 +               break;
  66 +       }
  67 +
  68 +       return ret;
  69 +}
  70 +
  71  static int pca955x_led_set(struct led_classdev *led_cdev,
  72                             enum led_brightness value)
  73  {
  74 @@ -512,6 +563,7 @@ static int pca955x_probe(struct i2c_clie
  75
  76                         led->name = pca955x_led->name;
  77                         led->brightness_set_blocking = pca955x_led_set;
  78 +                       led->brightness_get = pca955x_led_get;
  79
  80                         err = devm_led_classdev_register(&client->dev, led);
  81                         if (err)